The aim is to slow population growth on the range and work towards maintaining the appropriate management level of 70-140 wild horses in the McCullough Peaks herd management area, it says.
It says maintaining appropriate herd numbers will help preserve the rangelands, and balance wild horses with other public rangeland resources and uses.
It expects the use of PZP will reduce the need for large and costly helicopter removal operations in the future.
Bureau director Bob Abbey has signalled a change in focus with the wild horse programme, which has been criticised as being costly and inefficient, with around 40,000 horses now held in captivity - more than now exist on the western rangelands.
Changes proposed include more aggressive use of contraceptives, fewer roundups, greater public input and use of volunteers, and the exploration of public-private partnerships in the management of the horses.